2020 mack mp7 fuel in oil

I had that problem with a 2016 MP8. Changed injectors. 2 weeks later doing it again. They pulled all the injectors out and resealed them, then pulled the supply pump and resealed and checked it. 2 weeks later, doing it again. Another shop put another set of injectors in it and the problem stopped. Since it was under warranty the 1st time, they used reman injectors and one was defective. The 2nd set were new.

 

I am not sure about a 2020 but had two older ones with the gear driven supply pump leaking fuel fuel past the shaft. If I recall correctly the supply pump can be slide back and build pressure with the had pump to test.
A third one had plugs in the front of the block fuel galleys leaking. The plugs were loose like the locktite had desolved.
I would be looking at stuff under the valve covers and without the oil pan before I spent big bucks.